Examine source code of RightClickDefine

{
  "manifest_version": 2,
  "name": "RightClickDefine",
  "version": "1.0",
  "description": "Presents 2 right click options for highlighted text to open the definition in new tab.",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "16": "icons/icon16.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "permissions": [
    "contextMenus"
  ]
}